Portable lifting boom



y 0, 1958 G. K. EGGLESTON 2,835,402

PORTABLE LIFTING BOOM 2 Sheets-Sheet 1 Filed .Dec. 23, 1955 INVENTOR. G /'/b Qf/ K. 5/26 fox? A #orn 6 5/6 May 20, 1958 e. K. EGGLESTON 2,335,402

PORTABLE LIFTING BOOM Filed Dec. 23, 1955 2 Sheets-Sheet 2 INVENTOR. I G/fibe/"f K. g g/ea fan United States Patent Q PORTABLE LIFTING BOOM Gilbert K. Eggleston, Mansfield, Ohio, assignor to Pryor Manufacturing (30., Mansfield, Ohio, a corporation of Delaware Application December 23, 1955, Serial No. 554,973

3 Claims. ((31. 214-620) This invention relates to improvements in a portable lifting boom and more particularly to a conversion boom to be secured to any standard portable lifting truck having a forwardly extending lifting member.

An object of the present invention is to provide a light weight boom which may be quickly attached to a portable lift truck with the rear end of the boom pivotally mounted on the fixed vertical frame of the lift truck and a boom-lifting strut removably attached to a forwardly extending lifting member in a vertically movable frame of the lift truck. in this fashion, a standard truck may be quickly converted to a boom type lifting device.

Other objects and advantages of the present invention will be apparent from the accompanying drawings and description and the essential features thereof will be set forth in the appended, claims.

In the drawings,

Fig. l is a side elevational view of my device attached to a portable lift truck with a dot-dash position of the parts indicating how an object may be lifted from the floor.

Fig. 2 is a top plan view of the device of Fig. 1.

Fig. 3 is a fragmental sectional view, enlarged, taken along the line 33 of Fig. 1.

Figs. 4 and 5 are fragmental sectional views, enlarged, taken along similarly numbered lines of Fig. 2.

Fig. 6 is a fragmental sectional view, enlarged taken along the line 66 of Fig. 1; while Fig. 7 is a fragmental sectional view taken along the line 77 of Fig. 6.

l have chosen to show my invention as applied to a type of industrial truck made by Willamette Hyster Company of Portland, Oregon, but it will be understood by those skilled in this art that the boom may be mounted on almost any vertical lifting truck of the type described with the simple adaptations here recommended.

Figs. 1 and 2 show such an industrial truck which is provided with a motor within the housing 10 and suitably connected to the wheels 11 to drive the truck which is steered and controlled by a driver sitting on the seat 12. The truck here shown is more fully described in patents granted to George V. Johnson, No. 2,349,352, granted May 23, 1944- and No. 2,387,077, granted October 16, 1945.

As is usual in this kind of truck, a fixed vertical frame 13 having two main vertical side members rigidly fixed to the truck is provided with a lifting frame 14 which comprises two vertical parallel side members adapted to rise and fall vertically and riding on friction reducing rollers 15 which are seen in Fig. 2. The frame 14 and forks 16 may be lifted in any suitable manner, one construction shown in the above mentioned Patent No. 2,349,352 comprising a vertically extending hydraulic hoist 35, 40 which lifts the frame 14 which in turn lifts the bight in a chain 56. The two chains shown in the patent (but omitted here for clarity) have an end fixed 2,835,402 Patented May 20, 1958 to the frame 13 and an end fixed to the frame 16a which carries the bifurcated fork-like member 16--16 to which the portable boom of this invention may be attached. Lifting the hydraulic hoist 35, 4t) raises the forks 16.

The only change necessary in this standard truck to utilize the present invention is the fixing by any suitable means, such as by welding, of a lug 17 on each of the frame members 13 extending rearwardly therefrom for the attachment of pivot pin 18 as will presently be described.

The lifting boom of this invention is composed of two side members 19 which are secured by welding respectively to plates 2% at their rear ends which are spaced apart about the distance between the two vertical frame members 13 of the lifting truck. Specifically, they are positioned so as to lie snugly just outside of the lugs 17 as clearly shown in Fig. 3. These plates 20 are provided with suitable holes so that the pivot pin 18 passes through two of the plates 20 and two of the -lugs 17 as clearly seen in Fig. 3. The boom members 19 converge nearly to a point at the front end of the boom and are there rigidly connected together by welding a tie member such as the short piece of angle 21 to the two side members 19. Any suitable lifting connection may be attached to the member 21 and l have here fastened a lug 22 extending downwardly to which a book 23 is attached. Obviously a cable sling or a portable hoist might be fastened in this position. Suitable cross braces are provided as at 24 and 25 rigidly welded to the side members 19 so as to give a strong boom. To strenghten the boom against bending in a vertical plane, two tie rods 26 are provided generally parallel in vertical planes to the side members 19 but raised above the same by means of a block 27 on each side of the boom which is welded to the associated tie rod and associated side boom member 19. The tie rods are welded at both the front and rear end of the boom to their respective side boom members 19. The tie rods are also connected together by welding a bracing member 28 between them just above the blocks 27.

A lifting strut 29 is provided which is pivotally attached at its upper end to the main boom members 19 at an intermediate point thereof and this strut is provided at its lower end with means for attachment to the forks 16 while permitting pivotal action of the strut relative to the attachment means. As clearly shown in Figs. 2 and 4, the strut 29 comprises two side members which are spaced apart at their lower ends approximately the distance between the two forks 16 and which converge at their upper end to a point where they are welded to an angle member 31). This angle member is welded to a piece of tube 31 which is shorter in length than the distance between the side boom members 19 at that point. Snugly embraced within the tube 31 is a rigid bar 32 which is Welded at its opposite ends between the side boom members 19 and provides an additional strengthening member between the side members at that point. This bar 32 and tube 31 provide a pivot connection between the strut 29 and the main boom.

At its lower end, each strut 29 in welded to the midpoint of a short tube 33 as best seen in Figs. 6 and 7. The position of the member 29 is indicated in dot-dash lines in Fig. 6 as it would not normally show in the position from which the view of Fig. 6 is taken. Snugly but rotatably embraced within the tube 33 is a pin 34 which is welded at its opposite ends to a shoe 35 which is U- shape in section turned upwardly as shown in Fig. 6.

This is welded to another U-shape section 36 which opens downwardly and carries a set screw 37 threaded in one of the side flanges of the member 36 in position to frictionally engage one of the forks 16 when the shoe is in place. The strut 29 is preferably braced by a cross tie member 29a welded to both of the members 29.

The operation of my invention should now be clearly understood. To convert the standard fork lifting truck to a portable lifting boom truck, it is only necessary to fasten the rear end of the main boom in position by means of the pivot pin 18 passing through the lugs 17 already attached to the vertical frame 13 of the industrial truck. Each shoe 35, 36 at the lower end of the lifting strut 29 is attached to one of the forks 16 of the lift truck by means of its associated set screw 37. Referring to Figs. 1 and 2, it is obvious that the position of these shoes may be varied from front to rear of the lifting fork 16 which will give some control of the lowest and highest movements of the hook 23. It should be obvious that it would be very inexpensive to make several different lengths of boom utilizing this invention if the situation called for such construction. It will be seen from the drawings that most of members out of which I have constructed the boom and its attached lifting strut are circular in section and may be made of standard bars or tubes depending upon the load to be lifted. This renders my device very inexpensive to make.

It will be apparent to those skilled in this art that my improved portable lifting boom permits the operator to lift and place objects which normally cannot be handled by a standard self-propelled lift truck. It also eliminates the capital investment which would be necessary if one purchased a portable lift boom truck built only for this purpose. Utilization of this attachment for the standard self-propelled lift truck quickly converts such a standard truck to a portable lifting boom device. My improved boom attachment permits the removal and placing of items which are normally not accessible to a fork lift truck. It permits the handling of items which are stored or have to be removed from behind other objects. It permits the loading of heavy objects to stake body trucks where the height is not accessible from a floor level loading device. It also permits the handling of items from below the surface of the floor upon which the lift truck operates.

What is claimed is:

1. A load lifting boom device for attachment to a lift truck of the type having a fixed vertically extending frame and having a forwardly extending lifting member movable vertically relative to said frame; said boom device comprising a main boom having means at one end for pivotal attachment to a vertically extending truck frame, a lifting strut pivotally attached at its one end to said main boom intermediate the ends thereof, detachable means for attaching the other end of said strut to a lifting member of a truck, a pivotal connection between said other end of said strut and said detachable means, said strut being bifurcated at its lower end providing two arms, and said detachable means'comprising a shoe for each arm having a recess adapted to embrace a lift truck fork, said last named pivotal connection comprising aligned pivot pins, one in each shoe connecting its associated arm to the shoe, said main boom comprising two side members spaced apart horizontally, and said pivotal attachment of said strut to said main boom comprising a tube member rotatably embracing a pin member, one of said members rigidly attached to the upper end of said strut, and the other of said members rigidly connected between said side members to brace said boom.

2. The combination of claim 1 wherein said main boom side members are rigidly connected at the front end of said boom and diverge toward the rear, and said means for pivotal attachment to a truck frame comprises plates having aligned openings secured to the rear ends of said side members.

3. The combination of claim 1 including a tie rod extending along each side member and above the associated side member, each tie rod rigidly secured at its ends to its associated side member, each tie rod gradually rising from each end toward an intermediate point, and a rigid block secured between each tie rod and its associated side member at said intermediate point.

References Cited in the file of this patent UNITED STATES PATENTS 2,433,584 Turner Dec. 30, 1947 2,445,614 Flynn et a1. July 20, 1948 2,493,750 Bucksath Jan. 10, 1950 2,605,002 Graves July 29, 1952 2,704,615 Stokes et al. Mar. 22, 1955 

